Morbidity and mortality following early administration of amiodarone in acute myocardial infarction

Aims The objective of this study was to ascertain the effect of intravenous and oral amiodarone on morbidity and mortality in patients during the first hours after the onset of an acute myocardial infarction. Methods and Results A cohort of 1073 patients admitted to the CCU within 24h of the onset of symptoms of an acute myocardial infarction and heart failure (Killip and Kimball A-B) were randomized to receive amiodarone (n=542) or placebo (n=531) for 6 months. Because of the higher mortality, on an interim analysis, from a ‘high dose’ of amiodarone or placebo (516 patients) the protocol was changed to a ‘low dose’ or placebo (557 patients). Mortality with high doses of amiodarone was 16·30% vs 10·16% in the placebo group (P=0·04), whereas mortality with low doses was 6·61% vs 9·47% in the control group (P=0·20). Several non-fatal adverse effects were observed in 108 and 73 patients treated with amiodarone and placebo, respectively. Conclusion This study demonstrated that early administration of amiodarone in low doses to patients with an acute myocardial infarction may be used only if life-threatening arrhythmia justify its prescription. Conversely, when given in high doses, it might increase mortality.